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121.
122.
为了满足航天器桌面散态匹配试验测试需求,研制一种基于PC104总线的执行机构等效装置,详细阐述了等效装置的功能、工作原理、硬件电路设计、软件设计思想,该系统采用模块化、可配置软件架构设计,实现了正常、应急多测试工况一体化设计;应用严格的窗口比较器硬件电路设计技术,实现信号电压幅值的高精度采集,确保输入信号的可靠判定;利用FPGA技术突破信号脉宽高精度采集和信号延时高精度可控等关键技术,该系统实现了输入信号幅值、脉宽的实时采集、存储与显示,并按照事先设定的工作模式及配置参数,完成不同测试工况下输出信号的模拟反馈。试验结果表明,系统稳定可靠,人机界面友好,满足航天器多测试工况控制时序和功能检查需求。 相似文献
123.
Peter B. Luppa Carolin MüllerAlice Schlichtiger 《Trends in analytical chemistry : TRAC》2011,30(6):887-898
Point-of-care testing (POCT) is a laboratory-medicine discipline that is evolving rapidly in analytical scope and clinical application. In this review, we first describe the state of the art of medical-laboratory tests that can be performed near the patient. At present, POCT ranges from basic blood-glucose measurement to complex viscoelastic coagulation assays. POCT shortens the time to clinical decision-making about additional testing or therapy, as delays are no longer caused by transport and preparation of clinical samples, and biochemical-test results are rapidly available at the point of care. Improved medical outcome and lower costs may ensue.Recent, evolving technological advances enable the development of novel POCT instruments. We review the underlying analytical techniques. If new instruments are not yet in practical use, it is often hard to decide whether the underlying analytical principle has real advantage over former methods. However, future utilization of POCT also depends on health-care trends and new areas of application. But, even today, it can be assumed that, for certain applications, near-patient testing is a useful complement to conventional laboratory analyses. 相似文献
124.
针对课程改革的目的,结合教学实践,就概率统计课程建设和教学改革的必要性进行综合分析并主张:通过讲述概率统计理论发展史,引导学生明确学习重点;借助多媒体教学,整合教学大纲内容,系统教学;将理论与实际相联系,激发学生学习兴趣;立足基本理论,开设统计学软件实验课程. 相似文献
125.
This work deals with log‐symmetric regression models, which are particularly useful when the response variable is continuous, strictly positive, and following an asymmetric distribution, with the possibility of modeling atypical observations by means of robust estimation. In these regression models, the distribution of the random errors is a member of the log‐symmetric family, which is composed by the log‐contaminated‐normal, log‐hyperbolic, log‐normal, log‐power‐exponential, log‐slash and log‐Student‐t distributions, among others. One way to select the best family member in log‐symmetric regression models is using information criteria. In this paper, we formulate log‐symmetric regression models and conduct a Monte Carlo simulation study to investigate the accuracy of popular information criteria, as Akaike, Bayesian, and Hannan‐Quinn, and their respective corrected versions to choose adequate log‐symmetric regressions models. As a business application, a movie data set assembled by authors is analyzed to compare and obtain the best possible log‐symmetric regression model for box offices. The results provide relevant information for model selection criteria in log‐symmetric regressions and for the movie industry. Economic implications of our study are discussed after the numerical illustrations. 相似文献
126.
A. Chatterjee B. K. Chakrabarti 《The European Physical Journal B - Condensed Matter and Complex Systems》2006,54(3):399-404
We study here numerically the behavior of an ideal gas like model of markets having
only one non-consumable commodity. We investigate the behavior of the
steady-state distributions of money, commodity and total wealth,
as the dynamics of trading or exchange of money and commodity proceeds,
with local (in time) fluctuations in the price of the commodity.
These distributions are studied in markets with agents having uniform and
random saving factors. The self-organizing features in money distribution
are similar to the cases without any commodity (or with consumable
commodities), while the commodity distribution shows an exponential decay.
The wealth distribution shows interesting behavior: gamma like
distribution for uniform saving propensity and has the same power-law tail,
as that of the money distribution, for
a market with agents having random saving propensity. 相似文献
127.
X. G. Li Z. Y. Gao B. Jia R. Jiang 《The European Physical Journal B - Condensed Matter and Complex Systems》2006,54(3):385-391
Segregation effects commonly exist in granular mixtures
with difference in size, shape or density. In mixed traffic flow,
slow vehicle and fast vehicle, as two types of particles, have
different desired speed. We investigate the segregation along the
road in mixed traffic flow by using a symmetric two-lane cellular
automata model. A parameter D, which quantifies the degree of
segregation, is defined. We study the density dependency of the
parameter at different randomization probability. Simulation results
show that segregation is more obviously in free flow region. We
argue that the overtaking maneuvers have similar effect as
percolation in granular flow. 相似文献
128.
P. Csáki L. Csiszár F. Fölsz K. Keller Cs. Mészáros T. Rapcsák P. Turchányi 《Annals of Operations Research》1995,58(6):441-453
A flexible framework for Group Decision Support on PCs in Microsoft Windows environment is presented. WINGDSS does not replace human judgment but highly supports the entire process of decision making, from problem structuring to post-decision analysis. The latest version of WINGDSS is a modular, open system with a dynamical connection to relational databases, an interpreter for defining problem specific evaluation procedures, a lot of interactive features from setting up the tree of criteria until the sensitivity analysis on individual/group ranking. By providing tools for recursively redefining the decision problem, WINGDSS helps the decision makers in achieving a result satisfactory to the whole group.Research supported in part by the Hungarian Foundation for Scientific Research, Grant No. 2568 and by the Hungarian National Committee for Technical Research and Development, Grant No. 93-97-67-0553. 相似文献
129.
A covering array of size N, strength t, degree k, and order υ is a k × N array on υ symbols in which every t × N subarray contains every possible t × 1 column at least once. We present explicit constructions, constructive upper bounds on the size of various covering arrays, and compare our results with those of a commercial product. Applications of covering arrays include software testing, drug screening, and data compression. © 2002 Wiley Periodicals, Inc. J Combin Designs 10: 217–238, 2002; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/jcd.10002 相似文献
130.